Answers

2015-11-18T18:24:33+05:30
 let the height of the building be h m 
then AB =h m 
in right angle triangle PQR tan 60°=PQ/BQ
=>√3=30/BQ=>BQ
30/√3m=30√3/3m =10√3
in the trialgle ABQ
tan30°=AB/BQ 
=>1/√3=h/BQ =>h =BQ/√3
=>h =10√3/√3 =10
HENCE THE LENGTH OF BUILDING =hm=10m

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